On Jan 27, 3:16 pm, Reckoner <recko...@gmail.com> wrote: > I'm not sure this is possible, but I would like to have > a list of objects > > A=[a,b,c,d,...,z] > > where, in the midst of a lot of processing I might do something like, > > A[0].do_something_which_changes_the_properties() > > which alter the properties of the object 'a'. > > The trick is that I would like A to be mysteriously aware that > something about the object 'a' has changed so that when I revisit A, > I will know that the other items in the list need to be refreshed to > reflect the changes in A as a result of changing 'a'. > > Even better would be to automatically percolate the subsequent changes > that resulted from altering 'a' for the rest of the items in the list. > Naturally, all of these items are related in some parent-child > fashion. > > that might be a lot to ask, however. > > Any advice appreciated.
You should really look at Enthought's Traits package. It does exactly what you are asking for, and much, much more. See: http://code.enthought.com/projects/traits/documentation.php http://code.enthought.com/projects/traits/examples.php Using Traits, you could do the following: from enthought.traits.api import * class Child(HasTraits): state = Enum("happy", "sad", "bawling") class Parent(HasTraits): child = Instance(Child) @on_trait_change('child.state') def handler(self): print "new child state:", self.child.state bob_jr = Child() bob = Parent(child = bob_jr) bob_jr.state = "sad" # This would result in bob.handler() being called (Disclosure: I work at Enthought and have been using Traits heavily for the last 4+ years.) -Peter -- http://mail.python.org/mailman/listinfo/python-list
